Segment Information - Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Jul. 31, 2013	Jul. 31, 2012
Segment Reporting Information [Line Items]
Revenues from external customers	$ 32,003	$ 26,683
Operating earnings (loss) before income taxes	2,424	1,059
Domestic Operations [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	27,073	22,629
Intersegment revenues	1,404	730
Operating earnings (loss) before income taxes	3,182	1,884
International Operations [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	4,930	4,054
Intersegment revenues	486	504
Operating earnings (loss) before income taxes	557	246
Corporate [Member]
Segment Reporting Information [Line Items]
Intersegment revenues	(1,890)	(1,234)
Operating earnings (loss) before income taxes	$ (1,315)	$ (1,071)

This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 5

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- Definition

Amount of revenue from transactions with other operating segments of the same entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 27

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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